Résumé
Theobroma cacao L., is a diploid tree fruit species (2n = 2x = 20), originated from the South American rainforests. A criollo genotype, providing a high quality chocolate and highly homozygous, has been choosing by the ICGS to sequence the cocoa genome. A combination of Sanger and NGS technologies was chosen for sequencing the criollo genotype, with a genome coverage of 16,7 X. The assembly corresponds to 76% of the estimated genome size of the criollo genotype (430 Mb) and appears to cover a very large proportion of the euchromatin of the T. cacao genome, allowing to recover 97.8% of the transcriptome unigene resource. Annotations revealed 28,798 protein-coding genes. This first cocoa genome sequence was the support to inventory in the cocoa genome important gene families potentially involved in resistance and quality traits. Their localisation in the genome and their comparison with QTLs involved in these traits provide a large set of candidate genes. The inferred paleohistory of the T. cacao genome has highlighted the close evolutionary relationship of the T. cacao genome to the eudicot putative ancestor, as was also observed in grape. We propose an evolutionary scenario whereby the ten T. cacao chromosomes were shaped from an ancestor through only eleven chromosome fusions. It represents a new and simple model to study evolutionary processes, gene functions, genetics and biochemistry of tree fruit crops. A genome browser allows to access freely to the cocoa sequence data at the following website : http://cocoagendb.cirad.fr. (Texte intégral)